I grow P. rosettifolia for some years now, but it is puzzling to me. First I had difficulties with propagation, I noticed that the leaves rot very easily and you have to keep them rather dry, after that, it is no problem (just 1 plant per leaf seems to be the rule, not many as with violets).

But now I can grow them, and propagate them, and they look nice and healthy, but they never flower. I gave some away, which flowered a few weeks later! Clearly, they miss some kind of trigger, like a change in temperature or so. I tried putting one outside for some weeks last year, it survived (with some sunburn), but it didn't flower. (I have really cold nights, right now it gets to 10 degrees, even when the daytime temperature is 25-30 degrees).